Research On Voltage Redundancy And Torque Control Of Sensorless Permanent Magnet Synchronous Motor

With the development and progress of society,permanent magnet synchronous motors are widely used in various fields due to their simple structure,high power factor,and fast dynamic response.But when the permanent magnet synchronous motor is used in the medium and high speed domain,the induced electric potential is very likely to exceed the output voltage of the inverter,so the field weakening control is required.During the field weakening control,the output voltage range of the inverter will be limited,but the phase of the voltage vector is not limited.The constant current control is performed by the current given value,so as to ensure the fast response performance of the current controller on the basis of the field weakening control algorithm.For the maximum voltage that the inverter may output,the voltage redundancy needs to be determined.In this paper,for the voltage torque feedback control method,the terminal voltage is linearized,and a new type of control gain algorithm is obtained and cooperates with the overmodulation method of priority d-axis to achieve voltage redundancy control to ensure torque control performance.By applying the proposed new control algorithm to multi-pulse PWM in the over-modulation mode(modulation rate 1.15 or higher),the system control performance in the non-linear region can be improved,and the inverter output voltage utilization can be improved accordingly To a certain extent,the torque control characteristics can be improved.Using a position sensorless control method can reduce the size and cost of the motor,and enhance the overall reliability of the motor system.Therefore,this paper proposes a position estimation method based on the γ-δ estimation coordinate system under the full speed range.The extended electromotive force caused by the velocity and the injected signal is defined as a new type of synthetic extended electromotive force.The proposed extended electromotive force automatic adjustment method can automatically adjust the amount of voltage signal superimposition,and eliminate the influence of the extended induced voltage decrease caused by the decrease of the speed on the position estimation accuracy,so it can carry out the full speed range sensorless control.Therefore,it is possible to use a single estimation algorithm to estimate the position information from the start of the motor to the high-speed domain,so as to realize the positionless control under the full speed range.Finally,a position sensorless permanent magnet synchronous motor voltage redundancy control simulation model is established through the Matlab/Simulink simulation platform,and simulation results under different conditions are obtained through simulation experiments.The experiments show that the d-axis priority control is used in the torque feedback control The voltage utilization rate can be improved,and the back-EMF position estimation algorithm under the full speed range can achieve no position estimation well in different speed domains,and the estimation accuracy of position and speed is guaranteed.